Most imaging centers will have special protocols based on patient histories.

For MS, the MRI brain, which I'm sure is the MRI ordered by your doc, should include a sagittal FLAIR sequence, as well as post contrast imaging. If you are having visual symptoms, they should also include high resolution coronal sequences to assess the optic nerve.

You might want to make sure that your doc also orders a cervical spine MRI, as up to 20% of patients with MS will have normal brain imaging but detectable disease within the C-spine. It would be best to make sure this is ordered ahead of time that way both studies can be done at the same time. If you wait until your there and the c-spine was not ordered, you'd probably have to come back. MRI centers are usually heavily booked and its difficult to accommodate last minute studies that are not medical emergencies.

Remember that MS is a clinical diagnosis and imaging should only be used to confirm those findings. It can then be used to monitor disease.